CVE-2021-39251: debian debian_linux NULL Pointer Dereference
Vulnerability summary
CVE-2021-39251 is a high (CVSS 7.8) NULL Pointer Dereference vulnerability in debian debian_linux. EPSS estimates a 0.42% chance of exploitation in the next 30 days, higher than 35.9% of scored vulnerabilities.
Not severe (CVSS 6.7, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 10 · Related 6Timeline
- 07-09-2021PublishedVulnerability first disclosed.
- 02-12-2025Last modifiedVulnerability information updated.
Description
A crafted NTFS image can cause a NULL pointer dereference in ntfs_extent_inode_open in NTFS-3G < 2021.8.22.
CVSS metrics
5 scores · 4 sources · 2 versions- CVE.orgCNA6.7MediumCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:HDiffers
- OSV · UbuntuEcosystem advisory · calculated6.7MediumCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:HDiffers
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.42%
Chance of exploitation in the next 30 days
Percentile
36%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.42% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-476NULL Pointer DereferenceThe product dereferences a pointer that it expects to be valid but is NULL.
- CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Affected systems
Known conditions: local access, administrative account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian2 products
- ntfs-3g< 1:2021.8.22-2
- debian_linuxEOL9.0 | 10.0 | 11.0
Fedoraproject1 product
- fedoraEOL33 | 35
Redhat1 product
- enterprise_linuxEOL7.0 | 8.0
Tuxera1 product
- ntfs-3g< 2021.8.22
Ubuntu1 product
- ntfs-3g< 1:2013.1.13AR.1-2ubuntu2+esm1 | < 1:2015.3.14AR.1-1ubuntu0.3+esm1 | < 1:2017.3.23-2ubuntu0.18.04.3 | < 1:2017.3.23AR.3-3ubuntu1.1 | < 1:2017.3.23AR.3-3ubuntu5
5 vendors · 6 products
References
17 links- github.com/tuxera/ntfs-3g/security/advisories/GHSA-q759-8j5v-q5jpThird Party Advisory
- lists.fedoraproject.org/archives/…Vendor Advisory
- lists.fedoraproject.org/archives/…Vendor Advisory
